Brake system actuated by fluid pressure



March 27, 192& 1,663,579

A. ANDERBERG ET AL BRAKE SYSTEM ACTUATED BY FLUID PRESSURE Filed Aug. 18. 1926 4 Sheets-Sheet 1 flwler; fin ZerZer [11% 4714281221? 1721"]877 March 27, 1928. 1,663,579

A. ANDERBERG ET AL BRAKE SYSTEM ACTUATED BY FLUID PRESSURE Filed Aug. 18. 1926 4 Sheets-Shani March 27, 1928.

A.- ANDERBERG ET AL BRAKE SYSTEM ACTUA'IEDBY FLUID PRESSURE 4 Sheets-Sheet 5 Filed Aug. 1a. 1925 bE.EE@EH!".|.|u il.

& 1 w ia 3 March 27, 1928.

A. ANDERBERG ETAL BRAKE SYSTEM ACTUATED BY FLUID PRESSURE Filed Aug. 18. 1926 4 Sheets-Sheet 4 LWI'OIOI...

\ QOIOOOOOOOOOUOOII I W Inve-n Zord:

Anders Anderberg an] [n c Anders Ande rfiery Patented Mar; 27, 1928.

UNI-TED sira nunnns ANDERBERG nun ERIK annnnssnnnnnnne, orivmmvro, SWEDEN.

BRAKE SYSTEM ACTUATED BY FLUID PRESSURE Application filed August 18, 1926, Serial N01 130,036, and. in Sweden August 19, 1925.

This invention relates to a. brake system actuated by fluid pressure. 7

As is well known, two main types of air brakes exist, namely: the single-chamber brake in which the pressure acts'on one side only of the piston, and the two-chamber brake in which pressure is applied on both sides of the piston and 1n which movement 1s obtained by the: differencein the applied pressure. I

Each of these two types of brakes has well known advantages and disadvantages, and in order to utilize the advantages of both types it has already been proposed to combine the twobrakes into one single brake sys tem, but in such a construction however disadvantages still remain. In addition such combination has rendered the mechanical contrivances very complicated especially as regards the brake rigging which transfers the movement of the pistons to the brake shoes andalso with respect to the operating devices necessary for the operationgof the combined brake. 7 Thus, in this combination of both brake types each of the pistons moves full strokefor a complete braking-operation, so thatlarge air consumption cannot be avoided, which is the most prominent disadvantage of the two-chamber brake, and further the pistons act upon different piston rods, lost motion of thepistons being arranged in order to obtain cooperation thereof. x v I The subject of the present invention comprises .a' compressed air or other fluid actu ated brake combining the advantages of the conventional single chamber brake and -of the two-chamber brake but without the dis advantages pertaining to these two types. of brake. The invention comprises a combination of two brake types, one of which may be av single-chamber air brake or an electric brake, whilst-he other is an improved twochamber air brake, in which the improvement consists in that the pressures on both sides of the piston are only applied upon the actual application. of the brake, while under all other conditionsipressure is applied to oneside only of the piston. For the sake of simplicity it is assumed in the following description that the first named part ot the combination is constituted by a single-chamber air brake.

In the construction according to the invention both brakes act upon onenndthe same piston rod or the like, and by this means a considerably simplified arrange ment for mechanically transferring the movement from the piston rod to the brake shoes s obtained. Further the brakes act successively one after the other, so that the ber air brake comes into action and causes the actualbraking pressure to be imposed upon the brake shoes. i In thisway, a new principle tor'air brakes is utilizechin that the. air saving singlechambcr brake is utilized for eitectingthe relatively great movement necessary for bringing the brake shoes into contact with the wheels, while the two-chamber brake, be ing uneconomical from the air consumption point-of View, is used only to apply the actual brake pressure. a i

For this reason the single-chamber air brake may be constructed with a smaller cylinder diameter than hitherto, because this brake does 'nothave to overcome any sub stantial resistance. The air consumption therefore will also be less than heretofore and if for instance, as above stated, an electric solenoid brake is substituted for this single-chamber air brake, air consumption will obviously be totally avoided. As according to the present invention the twochamber brake is not utilized to accomplish a movement but instead is only utilized to apply the actual braking pressure, the piston will have a minimum stroke and therefore the air consumption (volume of length of stroke) will be, in spite of the cylinder having a larger diameter than. before, a fraction only of the air consumption necessary for operating the conventional two-chamber brakes.

As it is the single-chamber brake which eliects the actual movement of the brake shoes, itsspecial advantage, namely the quick action, is utilized; and as it is the two-chamber brake which effects the actual braking, the special advantage of this type is also made use of, namely that the applying and releasing of the brake may be performed successively and that its braking effect is not exhausted by repeated applications and releasings of the brake. In this way the disadvantages hitherto inherent in the of brake are totally avoided.

, I urthermore, as .bothbrakes act upon one two types 1,663,579 res PATENT OFFICE;

and the same rod, any lost motion is unnecessary, so that not only is the necessary transmission system considerably simplified but also the operating means are very much si1npler because of the cooperation of the brakes, which is the characteristic feature of the invention and which is achieved by the elimination of the complicated valve for controlling the cooperation of the pistons of both brakes. The so-called triple valve may also be considerably simplified,

The fact that the single-chamber brake or its equivalent is mainly utilized for bringing the brake shoes in contact with the wheels and for that reason has to make a stroke which under all conditions is dependent upon the distance between the brake shoes and the wheels, before the twochamber air brake comes into action, results in that the brake system according to the present invention to a certain degree eliminates the use of automatic slack adjusters which serve the purpose of keeping the slack constant. No such constant slack is required for the reliable func- 'tion of the present system, although obviously a further saving in air consumption may i be obtained by keeping the slack at a certain minimum value. This becomes however a very unimportant factor, as the air consumption of the single-chamber air brake according to the invention in fact is already very little and does not come into consideration at all if instead of this air brake its equivalent, not actuated by compressed air, is used.

The invention is diagrammatically illustrated 'in the accompanying drawing in which Figure 1 shows a general plan of the brake system according to the invention.

Figure 2 is a section through the triple valve.

Figure 3 shows a modification of a detail in Figure 1.

Figure 1 shows diagrammatically a modification of the air brake system according to Figure 1.

I Figures 5 to 7 show the rotary valve of Figure 4 in different positions.

Figure 8 shows the use of a solenoid brake in place of a single-chamber air brake.

Figure 9 is a sectional view of a pressureretaining valve.

Figure 1 discloses a combination of two brakes according to theinvention, in which one brake is assumed to be a single-chamber air brake and the other brake is a two-chamber air brake, The working operation of the latter is modified in comparison with older constructions by allowing the space on one side of the piston to be in communication with the atmosphere, when the brake is released. This will be more fully explained later.

Referring to the drawings 1 denotes the brake pipe which is connected by; means of the pipe 5, the triple valve 2 and the pipe 4 with the auxiliary air reservoir 3. The cylinder of the single-chamber air brake is indicated at 6 and the movable piston therein at 7. The piston rod 8 common to both brakes is securely connected to the piston T and extends from the cylinder 6 into the cylinder 9 of the two-chamber air brake, through the piston 10 of which the rod 8 is freely slidable but will be connected thereto in one direction of movement of the piston, in a manner hereinafter described. Upon the piston 7 acts a return spring 11 and upon the piston 10 acts a similar spring 12. This last namedspring is scarcely necessary for the function of the system but is utilized in order to obtain a certain predetermined position of the piston at brake release. The piston rod 8 needs no packing in the cover of the cylinder 6 and therefore passes freely through a central hole in the cover. The cylinder 9 of the two-chan'iber brake must however be provided with packings in both covers. For this purpose packing pistons 13 and the brake piston 10 are securely fixed to a central tube 1 1, through which the piston rod 8 freely passes, the tube 11 serving as guide for the latter,

Thecylinder 6 of the single-chamber air brake is in communication at one end through a pipe 15 with the triple valve 2 and at a short distance from the cover is also in communication through a pipe 16 with the pres sure space at one end of the cylinder 9 of the two-chamber air brake, while the other pressure space of the said cylinder 9 is in communication through a pipe 17 with the brake pipe 1, the drawing (Figure 1) showing the position of the parts when the brake is in released position.

In order to establish mechanical connection between the piston 10 of the two-chamber brake and the common piston rod 8, when the said piston moves in one direction, that is, upon the application of the brake (in a direction to the left in Figure 1) any kind of carrier or clutch device may be utilized. Figure 1 illustrates a preferred form of such a device which consists of a lever rigging 18 provided with clutches or friction shoes 19-engaging the piston rod 8, a pair of controlling springs 20 serving to increase the pressure of the friction shoes 19 upon the piston rod 8 to such an extent. that a firm connection between the piston 10 and the piston rod 8 is obtained without however preventing a longitudinal displace ment of the entire carrier or clutch device.

Figure 3 illustrates-another form of embodiment of the clutch device. like reference numerals denominating similar parts. In this case the tube 14 is connected by means of pivoted rods 21 to a conical sleeve 22 surrounding wedge like (conical) clutches 23 which surround the piston rod 8. The

a to act when the piston surfaces, may securely valve 53 therein, the longitudinal which clutches are, as before, influenced by controlling springs '20. Any other type of clutch device may however be adopted and the invention is not limited to the types above described, the matter of importance being that a clutch device exists between the piston 10 and the piston rod 8, which de vice acts in onetdirection only, that when the brakes are applied, and which does not prevent the return movement of the piston rod when the clutch action ceases, and further that thisclutch device only begins begins to move in the said one direction, and isimmediately released when the piston moves in the opposite direction. The piston rod 8 should be shaped in conformity with the surfaces on the clutch shoes Thus, it may be provided with teeth, grooves, threads or the like, so'that the clutch shoes, which have corresponding grip the piston rod without the possibility of sliding.

Thetriple valve 2 (Figurel) maybe of very simple construction, and a preferred form-1s shown in Figure '2, 111 which 52 is the valve casing having a movable slide displacement of the slide valve-53 being effected by a piston 24. The valve casing is divided by the piston 24; into two chambers, one of (under the piston) is incommunication through the pipe connection 25 and the pipe 5 (Figure 1) wviththe brake pipe 1, while the ehamberon the opposite (above) side of the piston 24, which also contains the slide valve 53, is in connnunication through the pipe connection 26 and the pipe 4 (Figure 1) with the auxiliary air reservoir 3. Both chamberswill be in communication with each other, when the valve corresponds to the release position of the brake, by means of a so calledlteed groove 27 which in known manner forms a bypass for the air in both chambers. The slide valve 53 is provided with a channel '28 adapted to effect communication of the pressure space of the cylinder 6 with the atmosphere by means of the pipe 15, pipe connection 29 and the passage 30, when the valve is positioned to correspond to the release position of the brake, while in the application position of the brake the slide valve closes the said communication with the at- "mospherebut brings the pipe connection29 in communication with the pipe connection 26; that is tosay, the auxiliary air reservoir 3 (Figure 1) is brought in communication withthe pressure space of the cylinder 6 of the single-chamber brake. The slide valve is axially displaced by the piston 2st through the intermediary of helical springs 31, and as shown in Figure 2 the upper spring 31 does not reach up to its abutment on the piston rod but leaves a space32 between the endof the spring and thesaid abutment. This space-32 corresponds "to an axialdisplacement of the piston (without exerting a compressing eflecton the spring) of such length only as will be suilicient to close the bypass 27. In order to yieldingly retain the slide valve in definite positions, it

is engaged by a ball 33 or the like actuated by a spring and adapted to be pressed into.

niences its movement for releasingthe brake shoes from the wheels.

The triple valve just described effects a sudden increase of pressure in the cylinder of the single-chamber air brake'and'therefore a quick movement of'the brake shoes towards the wheels, which in the present case the correct principle. Furthermore, on account or the locking device, the valve is practically unaffected by air waves generally originating in the system, when theconductor applies the brake, F or thisreason,

the conductors valve mayalso be sin'iplified,

the constructions of such valves hitherto in use having been very complicated, chiefly for reason of avoiding the said airwaves.

In working operation, upon the application of the brake the conductors valve connected to the brake pipe 1 is opened, as I is well known, and as soon as the difference betwe en'the pressure in the auxiliary reservoir 3 and that in the brake pipe 1 has be come so great that the locking of the slide valve 53 in the positionshown ill Fig. 2 is overcome, the-slide valve is suddenly axially displaced so thatfull communication is ob tained between the auxiliary reservoir 3 and the cylinder 6 of the single-chamber air brake. By this means the said brake is put into action and the brake shoes are by aquiek movement brought into contact with the wheels. If the pressure in the brake pipe 1 at this phase of operation had been kept at the value existing when the slide valve 53 changed its position, the efiected brake action would therefore be dependent on that pressure only which the single-chamber air brake could produce. At the same time that the piston 7 of the single-chz'imi'ierair brake is'moved towards the other end, the pipe 16 leading to one side of the piston 10 in the two-chamber airbrake is opened. A s howtherefore on the opposite side of the piston is still higher than the pressure in the cylinder 6 of the single-chamber brake, the two-chamber brake still remains out ol action. It thereupon the conductor further opens the conductors valve, the pressure in the brake pipe 1 is further decreased, so that the pressure therein is somewhat lower than the pressure communicated from the auxiliary reservoir 3 through the cylinder of the single-chamber brake to one side of the piston 10, which latter then commences to move in the direction of applying the brake, to an extent which depends on theditlerence in the pressures. Upon the movement of the piston 10, the clutch device connected thereto will engage the piston rod 8 which in this manner is also actuated by the two-chamber brake. The object of the springs is to keep the clutch device sutiiciently out of tion until the clutches 19 or 23 have received suflicient pressure to ensure a secure grip upon the piston rod 8. lVhen this said pressure is effected, the entireclutch device can follow the piston rod in its movement, the springs 20 being extended.

When the two-chamber brake is put into action in the above stated manner, the pressure of the brake shoes upon the wheels will be increased in the same proportion as the pressure in the brake pipe 1 is decreased. If, on the contrary, the pressure in the brake pipe 1 is increased the brake power will be correspondingly decreased, and by this means the brake power may be controlled at will and continuously without exhausting the effect of the brake system.

To release the brake, the pressure in the brake pipe 1 must be increased, whereby the braking action of the two-chamber brake will be gradually decreased. When the pres sures on opposite sides of the piston 10 are approximately equal, the said piston-10 returns to its initial position under the influence of the spring 12, the clutch device being simultaneously released from the piston rod 8. The piston 10 however could also be pressed back to its initial position without the help of the spring 12, it the pressure in the main pipe 1, before the release of the brake is completed, is increased, so that it surpasses the pressure communicated through the cylinder of the singlaehamber brake.

\Vhen thereupon the pressure in the main pipethus reaches the value which it is intended to have for release of the brake, the triple valve again changes its position and interrupts the communication between the auxiliary air reservoir 3 and the cylinder 6, which latter is brought into communication with the atmosphere, whereby the brake shoes are removed from the wheels while simultaneously the auxiliary air reservoir is again filled from the brake pipe, until the pressures therein are equal.

The single-chamber brake may be so dimensioned as to causesufticient braking action to be exerted upon an empty railway carriage, while the entire combinedbrake system is made operative when the carriage is loaded. With this in view the pipe 16 connecting the single chamber brakewvith the two-chamber brakeis provided with a three-way cock 3st (Fig. 1) one branch of which is in communication with the atmosphere. With an empty carriage, the cock is set so as to interrupt the commiuiication between the cylinders (Sand 9, at the same time that the cylinder 9 is connected with the atmosphere. In this position of the cock 3 1-, the single-chamber brake alone will be put into actionupon the reduction of pressure in the brake pipe 1. The pipe 15 which connects the triple valve 2 with the singlechamber brake is also provided with a threeway cock and wl en the single-chamber brake is to operate alone, the said cock 35 is placed in such dosition as to reduce its cross sectional area of free passage, that is to say the coo: acts as a throttle valve for the purpose of obtaining a slower action of the brake. The cocks 8t and 35 may be mechanically interconnected, so as to operate in unison when either cock is operated.

To effect complete releasingot' the brakes on a single loaded carriage in a train which may also comprise a number of loaded carriages while the brakes ot the said other carriages need not be released. the mode of operation is as follows, the three-way cook 35 being then also provided with a branch in communication with the atmosphere. The three-way cock 34- is set so as to connect the right-hand chamber in the cylinder 9 with atmosphere; that is to say, the cock is so set as to interrupt communication with cylinder 6, while pipe 16 (which leads to said righthand chamber) is in communication with atmosphere through the third branch of cook 34:. This position of cock (leaving, cock 35 out of consideration for the moment) corresponds to braking for empty carriages, in that the single-acting brake 6? only will function when the brakes are applied; i. e., the pressure from the auxiliary reservoir 3 passes through the triple valve 2 and the cock to the right-hand chamber in cylinder 6.

Now, then assuming the brakes are applied in the whole train, then the carriage in question would also have its brakes still appliedbut by means oi? the single-chamber brake 6-7 only,and not by the twochamber brake. However, since the complete release of the brakes of the carriage in question was desired, the position of the cook 35 also has to be changed, so that the righthand chamber ot'cylinder (3 will communicate with the atmosphere through the third branch of cook 35, communication with the L brake shoes in contact with the wheels, for

instance the above described single chamber ir brake may be used for this purpose.

Thus, by means of the above described arrangement ot a plurality of two'chamber brake pistons on a common tube-like member and having a common clutch device, it is possible to obtain a large total piston area, while the diameters of the brake cylinders are comparatively small. Further, by having each of the two-ch amber brake cylinders connected, above stated, with the brake pipe and with the pressure pipe from the device "for applying the brake shoes, it is possible to cut in and cut out respectively by means of special cooks the number of cylinders which are considered necessary or unnecessary. By this means it will be possible, as aforesaid, to vary the maximum brake power witnin wide limits. It however should be specially emphasised that this capability of varying the maz-iimum brake power is ob tained without eliminating or reducing the advantages of the brake system according to the present invention. The said capability Y is further obtained without complicating the rake system or without increasing the costs of manutacturo to a considerable extent. It further pointed out that no other system of through-brakes for trains, as far is known, is capable of offering more than at the most two tllfielellt maximum brake powers (generally one for empty carriages and one iior loaded carriages), and to adapt the known systems for more than two brake powers could only be eii'ected at the expense of very complicated and very costly contrivances.

That a brake system which may be set to give one'mat-:imum brake power for empty carriages and one for loaded carriages cannot be considered as :tully satisfactory for long goods trains will be clear from the fact that the complete application of the brake of a wagon (that is the pressure of the brake shoes upon the wheels expressed in percent of the pressure or the wheels upon the rails), when it is empty, is about 90% and when it is fully loaded about only. It, therefore, is quite obvious that this considerable diii erence in the brake eilect causes extremely dii'ierent retardations upon the empty and fully loaded wagons respectively, and the result thereof will be that the coupling gears oi? the wagons will be subjected to violent imparts and jerks which in many cases cause a breakage thereof.

It, therefore, the maximum brake power for goods wagons could be setto correspond to empty. halt-loaded and fully loaded wagons, the brake effect obviously would be more even throughout the whole train and also the reta'rdatitm of the wagons would be more equal, so that the objectionable jerks and impacts would be eliminated.

neeaave The brake system according to the present invention may very easily be arranged to effect various brake powers and for this reason, it is especially adaptable for brakes in goods trains. The modification shown in Fig. 1 is particularly arranged to vary the brake power according to its application on empty, halt-loaded and fully loaded wagons, respectively. The device for bringing the brake shoes in contact with the wheels consists of a single-chamber air brake 01' the kind described above. In the position of the parts shown in Fig. 4; the brake system is set to suit fully loaded wagons, the device for applying the brake shoes and the pistons in the brake pressure cylinders being in released position.

If the brake system according to Fig. 1 is to be used for halt-loaded wagons, the cylinder 9 is cut out by interrupting its connection with the brake pipe 1 (through the pipes 17, 17) and with the pressure pipe 16, 16 from the brake shoe applying device. ltis however not sufficient, as stated above, to only close the said connections leading to the cylinder 9, for a possible difference in pressure in the said cylinder (that is, on both sides of the piston 10) must be overcome. F or this reason the pipes 17 and 16 must be connected to the atmosphere or else connected with each other, so that the pressure is balanced on both sides of the piston 10h Amongst these two possibilities of balancing the pressure, the first named method (the connection to the atmosphere) to be preferred, and for this purpose the closing of the pipes 16, 16 and 17, 17 is preferably carried into effect by three-way cocks, whereby the pipes are connected to the atmosphere as soon as their interconnection is interrupted.

In the same manner as the cylinder 9 is cut out, when the brake system is required to function on halt-loaded wagons, the cylinder 9" may also be cut out when the brake system is to be set for an empty wagon.

In order to enable the brake on single wagons to be released without necessitating an increase of pressure in the brake pipe, the pipes 16 and 16? and 17 and 17 leading to the cylinder 9 must be arranged so as to be closed by three-way cocks. If these three-way cocks are so set that the connections between the pipes 16 and 16, and 17 and 17 are interrupted and the pipes 16 and 17 are connected with the atmosphere, the cylinder 9 is also put out of action.

Thus, in order to release the brake on a fully loaded wagon it is necessary to cut out the cylinders 9, 9 and 9. whereby the two chamber brake pistons will be pressed by the springs 12- into their initial position. There remains however to cause the brake shoe applying piston 7 to occupy release position, which may be achieved in the manating device, so that theycould be set byinsane:

sion of a three-way cock in the pipe 15, by

means of which the connection with the auxiliary reservoir is interrupted, and the pressure space in the cylinder 6 is connected with the atmosphere). 4

In the embodiment diagrammatically shown in'Fig. 4 and having pipes or channels for cuttingin and out-respectively the connection with the brake pressure cylinders rom the brake pipe and auxiliary reservoir (through the brake shoe applying device) there will be required seven three-way cocks. To set all these cocks into correct position in volves naturally waste of time. It is true, they could be provided with a common opermeansof a handle, but such a device together with the costs of the three-way cocks is not desirable.

To eliminate thesedrawbacks ofaccomplishing the controlling of the brake etfect by the intermediary of three-way cocks and to substitute a single valve device for the same, obviously is the ideal solution of the problem under consideration and in addition more in unity with the simpleconstruction of the brake system according to the present invention. A valve device serving this purpose is shown in Fig. 4 as at 36.

The said valve 36 consists of a flat circular disc into which the pipes 16, 16316". 16 and 17 17, 17 l7 -open. The face of the disc is covered by a rotary valve having cavities 37 and 38 respectively, by means of which, for instance in the position shown in Fig. 4 adapted to serve on a fully loaded wagon, the pipe 16 is in communication with the pipes 16 16 and 16 with the pipes 17, 17 and 17.

In Fig. 5' the valve 36 is shown set to serve on a half-loadedwagon. As stated above, in, this case the pipe 16 should no longer be in communication with the pipe 16 nor the pipe'17 I both pipes 16 and l7tshould be connected with theatmosphere. This can be effected by rotating the valve so much as to move the cavities 37 and 38 respectively out of register with the mouths the mouths of the pipes 16 and 17 respectively. These cavities '39 and 40 are in com munication with each other by means of a. channel 41 connected with the atmosphere. Thus, by a fraction of a revolution of the valve 36, the cylinder 9 has been cut out.

In a. similar manner the cylinder 9 may be cut out, when the brake is to act on an empty wagon. The position of the valve in this case is shown in Fig. 6. p

' If the-brake on-a single Wagon is to be possible to release,

and the pipe 17 with the pipe 17,- but of the pipes 16*- and 17" respectively. By the said rotation however two other cavities 39 and40 respectively have been'placed in register with 'mum brake efi'ect.

released. without increasing the pressure in the main pipe, it will be necessary to also cut out the cylinder 9 and thereupon to. reduce the pressurein the pressure space of the cylinder 6 (that is, the pressure of the auxiliary reservoir) to such an extent, for instance, that the triple valve 2 is reversed to correspond tothe release position. All

7 these operations are carried outin the modification shown in Fig. 4'by setting the valve 36' so as to occupy the position shown in Fig. 7. It is to be noted that in this position of the valve 36, the discharge cavity. 40 does not extend up to the mouth of the pipe 17. By this means it, therefore, is

by rotating the valve 36 into. thev position as shown in Figs 7, the brake of a single Wagon which is coupled to the brakepipebeing under pressure, without thenecessity. of altering this pressure.

The rotary valve member of the valve 36 should be provided with a spring which has the tendency to move the said valve member from the position; shown in, Fig. 7 into. the position shown in Fig.6, so thatthe operating handle, when the completerelease 0 the brake has been accomplished, automatically returns to the position corresponding to the braking action on an empty wagom The rotation of the be effected from each and, ineach. of three positions ofthe op-v crating handle corresponding to an. empty, half-loaded or fully loaded wagon, a locking device should be provided to prevent the rotary valve from moving by itself into another position.

If the pressure in the brake pipe, when the brakes are released, is for instance 2-5 atmospheres in a brake system according to the present invention, maximum brake power may preferably be obtained by dischargingall compressed air from the brake pipe. It is however possible to couple a wagon having a brake system of: the just mentioned kind to'a train, the brakes of the other wagons of which are actuated by a difi'erent type of air brakes, for instance, a type requiring 5 atmospheres inthe brake pipe, when the brakes are released, and about 2.5 to 3atmospheres to obtain maxi- In such case the pressure in the right hand pressure space of the two chamber a'ir brake according to the present system, therefore, should not be permitted to sink lower than about 2.5 atmospheres in the brake pipe and atmospheric pressure in the right hand pressure space of the twochamber air brake. This is achieved by the provision in the pipe 17 of a pressure retainvalve may of course side of the wagon,

ing valve, that is to say a valve which only the forcing in of air from the pipe 17 into the said pipes 17, 17 and 17 in the ordinary manner. In this way maximum brake eti'ect isobtained in the brake system according to the present invention in the same manner as obtained in the brake systems of the other types above mentioned.

The presssure retaining valve may be of any conventional type and may consist, as illustrated in Fig. 9, of a cylinder 59 in. which aipiston valve or slide 60 reciprocates against the action of a spring 61, said piston being provided with a check valve 62 and, further, with small passages 63. The power 0t spring (31 corresponds to a certain minimum pressure acting on the check valve 62. The operation of this pressure retaining valve is as follows The nipple or on the valve casing or cylinder 59 being connected to themain pipe 1 and the nipple 65 to the left-hand chamber of the double-chamber brake, and the pressure in the main pipe being for example 5 atmospheres, while the pressure above the check'valve is about 4.5 atmospheres, the piston 60 will be moved upward, assisted. by the spring 61, and the check valve 62 opened, thereby causing a flow of pressure fluid from nipple 64: through nipple 65 until th pres sure above the check valve has also reached the value of 5 atmospheres. This corresponds to the position of released brakes. When the brakes are to be applied, the pressure in the main pipe and, hence below the piston 60 will be lowered so that the pressure above the check valve will press the biston 6O downward, the excess pressure fluid escaping through the passages 63. It, now, it is intended that the pressure above the check valve is never to fall below a certain predetermined value, for instance 2.5 atmospheres. while the pressure in the main pipe may tall to 0 atmosphere, the spring 61 should have such dimensions that it will keep the balance against the pressure above the check valve and press the piston 60 upward, the pressure above the check valve closing the latter. If, however. the check valve is to be cut out,-i.t will only be necessary to screw the spindle 66 u nvard, whereby the check valve is litted from its scat, leaving a passage 67 in the body ot the piston 60 free, so that open communication is thus established between the nipples 6 1- and ($5.

The said pressure retaining valve may obviously be provided with a by-pass, so that it may be cut out, when the train consists of wagons having brake systems of the type according to the present invention only. In this case the lower pressure in the brake pipe can be again applied, which obviously is the most advantageous under all circumstances and considerations.

It is quite obvious that the pressure rctaining valve may also be adjustable for different minimum pressures in the right hand pressure space of the two-chamber brakes. This adjustment and also the rendering of the bypass effective may preferably be achieved by means of a handle which may be in the different positions provided witlrlocking devices and marked, for instance, with the names of the brake systems to which they should be applied.

By means of the present invention all advantages incidentalto single-chamber brakes and two-chamber brakes have been taken care of, in that the short brake stroke and the small air consumption of the singlechamber brake and the capability of the two-chamber brake of successively releasing the brakes and, without exhaustion, alternately releasing and applying the brakes repeatedly have been successfully utilized. At the same time the disadvantages of the older constructions have been eliminated, in that the air consumption of the two-chamber brake has been diminished to a minimum and the combination of the latter with the single-chamber brake or its equivalent has been accomplished in a manner which extremely simplifies the construction of the brake system with respect to the transmission means between the piston rod, common to both brakes, and the brake shoes, as also with respect to the operating devices. On electric railways having compressed air brakes, the single-chamber air brake may be replaced, using extremely simple contrivances, by an. electric device, and by this means the air consumption is further reduced to a negligible amount, so that the compressors, the auxiliary reservoirs and so on may be made of smaller dimensions than hereto-tore, which obviously involves all imaginable advantages in utilizing the im proved brake system on electric railways.

o claim r 1. A brake system actuated by fluid pressure having two operating devices of different types, in which one of the said operating devices consists of a brake having quick action and relatively small brake power while the other operating device consists of an air brake having small movement and, in relation to the first named device, great and successively controllable brake power, the

said two operating devices cooperatively acting upon a common rod by means 0t which the brake motion is transferred to the brake shoes. l

2. A fluid actuated brake system having two operating devices of diiierent types connected with an auxiliary reservoir and a brake pipe, comprising a single-chamber air brake adapted to move the brake shoes into contact of limited pressure'with the wheels, a two-chamber air brake adapted to apply the actual brake pressure, a piston rod comn operating device consists of an air brake having small movement and, in relation to the first named device, great and successively controllable brake power, the said two operating devices acting upon a common rod by means of a mechanism automatically establishing a releasable connection between said rod and the brake of large braking power when the piston of said latter brake moves in one direction" and automatically releasing the connection when said piston moves 20' in the opposite direction. a v

4'. A fluid actuated brake system having two operating devices of different types connected with an auxiliary reservoir and a brake pipe, said two operating devices cooperatively acting upon a common piston rod and comprising a two-chamber air brake and asingle-chamber air brake having its cylinder connected to the auxiliary reservoir by means of a triple valve connected also to the brake pipe, said cylinder being in communication with the pressure space on one side of the piston of the two-chamber brake, while the pressure space on the other sideof said piston is in communication with the brake'piper H v p 5. A fluid actuated brake system having two operating devices of diiferent types connected with an auxiliary reservoir and a brake pipe, said twoloperating devices cooperatively acting upon a common piston rod and comprising a two-chamber air brake and a single-chamber airbrake having its cylinder connected to the auxiliary reservoir by means of a triple valve connected alsoto the brake pipe, said cylinder being in communication withthe pressure space on one side of the piston of the two-chamber brake; while the pressure space on the other side of said piston'is' in communication with the brake pipe,-whereby the connection be tween the two difierent brake types at the cylinder of the single-chamber brake is effected at. such a" point that the air pressure applied to the single-chamber brake only transferred to the two-chamber brake after the single chamber brakepiston has moved at least the greatest portion of its stroke for applying the brake shoes.

6. A fluid actuated brake system having two operating devices of different types connected with an, auxiliary reservoir and a brake pipe, said two operating devices'cooperatively acting" upon a common piston rod comprising a two-chamber ai'r and single chamher air brake suc'ha way that the its cylinder connected to the auxiliary reservoir by means of atriple v alvc connected also tothe brake pipe', said cylinder being in communication with thepressure space on one side of the piston of the two-chamber brake, while thepressure spacefon the other side of said piston is in communication with the brake pipe, the communicationbetween said brake pipe and the two-chamber brake being permanently open and the connection between the single and the two-chambered brakes being efiected at a point on the c linder of the single-chamber brake, which point is in communication with the free air when said single-chamber brake is in releasedposition V V 7. A fluid actuated brake system having two operating devices of different t pes' on nccted with an auxiliary reservoirand a brake pipe, said two operatingdevicesco operatively acting upon a cominon piston rod and comprising asingle and'a two: chambered air brake, the piston rod of the singlechamber brake passing; freely through a central aperture in the piston of the ma chamber brake and coac'ting with" a clutch means consisting at releasable clutch meta: ber's; surrounding the piston rod amt connected with thepiston of, the two-chamber brake, said clutch means acting automatically'in such a way that th piston' of the two-chamber brake is connected'to' the pis ton rod when moving in a' directionfor apfplying a brake pressure and released from the piston rod whennioving in the opposite direction 7 I z v I 8; A fluid actuated brake system having two operating devices of difieren't; ty esgin which one of the said operating devices c'p'n sists of a brake having qui k action andrelatively small brake power while the other 0 5: A

crating device consists ofa two-chamber air brake having small movementand, in re; lation to the first named d'evice," great and successively controllable brake pewer; the said two operating devices cooperatively set;

n; up ec dn fed by means or which the brake motion is transferred o theme-e shoes whereby the said"- rod forms the-piston rod ofv the two-chamber brake" and passes freely through a centralaperture in the pie: ton ofsaid brake; j clutch means releasably connecting the two chambci air "brak'epist'on with" said rod andacting automatically in said piston is connected to the rodwhen moving in one directionfffor applying a brake pressure and released from the" rod when moving in the'soppositeidirec tion. I i W 9'." A flu'id; actuated! brake s stem" having two operating 3 evices of difierent typ which one of t'h e said operating device sists of a brake having qaick scans and tively small (brake power while th air brake having small movement and, in relation to the first named device, great and successively controllable brake power, the said two operating devices cooperatively acting upon a common rod by means of which the brake pressure is tranferred to the brake shoes, whereby the said rod forms the piston rod of the two-chamber air brake piston in the central part of which piston is arranged a tubular member, through which the rod freely passes, a releasable clutch member being connected with the two-chamber air brake piston and automatically coacting with the said rod in such a way that the said piston is connected with the rod when moving in one direction for applying a brake pressure and released when moving the opposite direction.

10. A fluid actuated brake system having two operating devices of different types con nected with an auxiliary reservoir and a brake pipe, said two operating devices cooperatively acting upon a common piston rod and comprising a short-stroke twochamber air brake and a relatively-longstroke single-chamber air brake having its cylinder connected to the auxiliary reservoir by means of a triple valve, a three-way cock being provided in the connection between the single-chamber air brake and the triple valve and arran ed in such a way that it may serve to break the said connection and toset the single-chamber air brake cylinder in communication with the atmosphere.

11. A fluid actuated brake system having two operating devices of different types connected with an auxiliary reservoir and a brake pipe, said two operating devices cooperatively acting upon a common piston rod and comprising a short-stroke twochamber air brake and a relatively-longstroke single-chamber air brake having its cylinder connected to the auxiliary reservoir by means of a triple valve which is also connected with the brake pipe, and with the two-chamber air brake cylinder, the connection being effected at a pointof the singlechamber air brake cylinder, which point is in communication with the atmosphere when said single-chamber brake is released, said connection being provided with a three-way cock by means of which the communication between the air brake cylinders may be interrupted and the two-chamber air brake brought in communication with the atmosphere.

12. A fluid actuated brake system having two operating devices of difierent types, in which one of the said operating devicesrconsists of a brake having quick action'and relatively small brake power 'while the other operating device consists of a two-chamber air brake having small movement and, in rela tion to the first named device, great and successively controllablebrake power, the said two operating devices cooperatively acting upon a common rod by means of which the brake motion is transferred to the brake shoes, the two-chamber air brakepiston being releasably connected to said rod by clutch members connected with said piston and automatically acting upon the rod in such a way that the piston is connected to the rod when moving in a direction for applying a brake pressure and released when moving in the opposite direction, the said piston being spring actuated for bringing it back into normal position corresponding to released brakes when the pressures on both sides of the piston permit of such return action.

13. A fluid actuated brake system having two operating devices of different types connected with an auxiliary reservoir and a brake pipe, said two operating devices cooperatively acting upon a common piston rod and comprising a two-chamber air brake and a single-chamber air brake, of which the piston of the first-named brake is detachably coupled to the piston rod, the single-chamber air brake having its cylinder connected to the auxiliary reservoir by means of a slidable triple valve also connected to the brake pipe, said triple valve being actuated by a piston through the intermediary of springs and provided with lost motion of an extentto interrupt the communication established on both sides of the said piston by means of a bypass before the piston can actuate the slide valve through the intermediary of the said springs.

14:. A fluid actuated brake system having two operating devices of different types connected with an auxiliary reservoir and a brake pipe and comprising a twochambered and a single-chambered air brake cooperatively acting upon a common piston rod in relation to which the two-chamber air brake piston is detaehably coupled, a connection between the single-chamber air brake cylinder and the auxiliary reservoir, a triple valve also connected with the brake pipe arranged in said connection and comprising a slide valve actuated by a piston through the intermediary of springs and provided with lost motion of such an extent as to interrupt a communication established on both sides of the said piston by means of a by-pass before the piston can actuate the slide valve through the intermediary of said springs, the slide valve at both of its end positions coacting with looking devices, the locking action of which must be overcome by the piston before the valve can be moved.

15. A brake system actuated by fluid pressure having a number of" operating devices cooperatively acting upon one and'the same rod by means of which the brake pressure is transferred to the brake shoes, one of said operating devices being a quick action brake of relatively small brake power and each of the others a two chamber air brake of small movement and, in relation to the first named brake device, great and successively controllable brake power. 1

16. A brake system actuated by fluid pressure having a number of operating devices cooperatively acting upon one and the same rod by means of which the brake pressure is transferred to the brake shoes, one of said operating devices being a quick action brake of relatively small brake power and each of the others a two-chamber air brakeof small movement and, in relation to the first named brake device, great and successively controllable brake power, the. pistons of saidilast named air brakes being detachably coupled to the common'rod by clutch means automatically acting in such a manner that the pistons of the two-chamber air brakes are connected to the rod when moving in a direction for applying a brake pressure and released from the rod when moving in the opposite direction.

17. A brake system actuated by fluid pressure having a number of operating devices cooperatively acting upon one and the same rod by means of which the brake pressure is transferred to the brake shoes, one of said operating devices being a quick action brake of relatively small brake power and each of the others being a two-chamber air brake of small movement and, relatively to the first named brake device, great and successively controllable brake power, the pistons of said last named airbrakes being rigidly connected to each other so as to move in unison and detachably coupled to the common rod by a common clutch means automatically acting in such a manner that the pistons of the two-chamber air brakes are connected to the rod when moving in a direction for applying a brake pressure and released from the rod when moving in the opposite direction.

18. A brake system actuated by fluid pressure having a number of operating devices connected with an auxiliary reservoir and a brake pipe and cooperatively acting upon one and the same piston rod by means of which the brake pressure is transferred to the brake shoes, one of said operating devices being a single-chamber air brake and each of the others being two-chamber air brakes, the pistons of the last named air brakes being rigidly connected by means of a substantially central sleeve serving as guide for'the piston rod, said sleeve being detachably coupled to the piston rod by clutch means automatically acting in such a manner that the pistons of the two-chamber air brakes are connected to the piston rod when moving in unison in a direction for applying a brake pressure and released from the piston rod when moving in the opposite direction.

19. A brake system actuated by fluid pressure having a number of operating devices cooperatively acting upon one and the same piston rod by means of which the brake pressure is transferred tothe brake shoes, one of said operating devices being a singlechamber air brake connected with an auxiliary reservoir by means of a triple valve also connected to a brake pipe and each of the other operating devices being a twochamber air brake separately connectible with the single-chamber air brake and the brake pipe by means of a common valve member, said two-chamber air brakes having pistons rigidly connected with each other and detachably coupled to the common piston rod by clutch means automatically acting in such a manner that the pistons of the two-chamber air brakes are connected to the piston rod when moving in unison in a direction for applying a brake pressure and released from the said rod when moving in the opposite direction.

In testimony whereof we have signedour names to this specification.

ANDERS ANDERBERG. ERIK ANDERS ANDERBERG. 

